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Annotation of coherent/g/usr/bin/me/basic.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * The routines in this file move the cursor around on the screen.
        !             3:  * They compute a new value for the cursor, then adjust ".".
        !             4:  * The display code always updates the cursor location, so only moves
        !             5:  * between lines, or functions that adjust the top line in the window
        !             6:  * and invalidate the framing, are hard.
        !             7:  */
        !             8: #include       <stdio.h>
        !             9: #include       "ed.h"
        !            10: 
        !            11: /*
        !            12:  * Move the cursor to the beginning of the current line.
        !            13:  * Trivial.
        !            14:  */
        !            15: gotobol(f, n)
        !            16: {
        !            17:        curwp->w_doto  = 0;
        !            18:        return (TRUE);
        !            19: }
        !            20: 
        !            21: /*
        !            22:  * Move the cursor backwards by "n" characters. If "n" is less than
        !            23:  * zero call "forwchar" to actually do the move. Otherwise compute
        !            24:  * the new cursor location. Error if you try and move out of the buffer.
        !            25:  * Set the flag if the line pointer for dot changes.
        !            26:  */
        !            27: backchar(f, n)
        !            28: register int   n;
        !            29: {
        !            30:        register LINE   *lp;
        !            31: 
        !            32:        if (n < 0)
        !            33:                return (forwchar(f, -n));
        !            34:        while (n--) {
        !            35:                if (curwp->w_doto == 0) {
        !            36:                        if ((lp=lback(curwp->w_dotp)) == curbp->b_linep)
        !            37:                                return (FALSE);
        !            38:                        curwp->w_dotp  = lp;
        !            39:                        curwp->w_doto  = llength(lp);
        !            40:                        curwp->w_flag |= WFMOVE;
        !            41:                } else
        !            42:                        curwp->w_doto--;
        !            43:        }
        !            44:        return (TRUE);
        !            45: }
        !            46: 
        !            47: /*
        !            48:  * Move the cursor to the end of the current line. Trivial.
        !            49:  * No errors.
        !            50:  */
        !            51: gotoeol(f, n)
        !            52: {
        !            53:        curwp->w_doto  = llength(curwp->w_dotp);
        !            54:        return (TRUE);
        !            55: }
        !            56: 
        !            57: /*
        !            58:  * Move the cursor forwards by "n" characters. If "n" is less than
        !            59:  * zero call "backchar" to actually do the move. Otherwise compute
        !            60:  * the new cursor location, and move ".".  Error if you try and move
        !            61:  * off the end of the buffer. Set the flag if the line pointer
        !            62:  * for dot changes.
        !            63:  */
        !            64: forwchar(f, n)
        !            65: register int   n;
        !            66: {
        !            67:        if (n < 0)
        !            68:                return (backchar(f, -n));
        !            69:        while (n--) {
        !            70:                if (curwp->w_doto == llength(curwp->w_dotp)) {
        !            71:                        if (curwp->w_dotp == curbp->b_linep)
        !            72:                                return (FALSE);
        !            73:                        curwp->w_dotp  = lforw(curwp->w_dotp);
        !            74:                        curwp->w_doto  = 0;
        !            75:                        curwp->w_flag |= WFMOVE;
        !            76:                } else
        !            77:                        curwp->w_doto++;
        !            78:        }
        !            79:        return (TRUE);
        !            80: }
        !            81: 
        !            82: /*
        !            83:  * Goto the beginning of the buffer.
        !            84:  * Massive adjustment of dot. This is considered to be hard motion;
        !            85:  * it really isn't if the original value of dot is the same as the
        !            86:  * new value of dot.
        !            87:  * Normally bound to "M-<".
        !            88:  */
        !            89: gotobob(f, n)
        !            90: {
        !            91:        curwp->w_dotp  = lforw(curbp->b_linep);
        !            92:        curwp->w_doto  = 0;
        !            93:        curwp->w_flag |= WFHARD;
        !            94:        return (TRUE);
        !            95: }
        !            96: 
        !            97: /*
        !            98:  * Move to the end of the buffer.
        !            99:  * Dot is always put at the end of the file (ZJ). The standard screen code does
        !           100:  * most of the hard parts of update. Bound to "M->".
        !           101:  */
        !           102: gotoeob(f, n)
        !           103: {
        !           104:        curwp->w_dotp  = curbp->b_linep;
        !           105:        curwp->w_doto  = 0;
        !           106:        curwp->w_flag |= WFHARD;
        !           107:        return (TRUE);
        !           108: }
        !           109: 
        !           110: /*
        !           111:  * Move forward by full lines.
        !           112:  * If the number of lines to move is less than zero, call the backward line
        !           113:  * function to actually do it. The last command controls how the goal column
        !           114:  * is set. Bound to "C-N". No errors are possible.
        !           115:  */
        !           116: forwline(f, n)
        !           117: {
        !           118:        register LINE   *dlp;
        !           119: 
        !           120:        if (n < 0)
        !           121:                return (backline(f, -n));
        !           122:        if ((lastflag&CFCPCN) == 0)             /* Reset goal if last   */
        !           123:                curgoal = curcol;               /* not C-P or C-N       */
        !           124:        thisflag |= CFCPCN;
        !           125:        dlp = curwp->w_dotp;
        !           126:        while (n-- && dlp!=curbp->b_linep)
        !           127:                dlp = lforw(dlp);
        !           128:        curwp->w_dotp  = dlp;
        !           129:        curwp->w_doto  = getgoal(dlp);
        !           130:        curwp->w_flag |= WFMOVE;
        !           131:        return (TRUE);
        !           132: }
        !           133: 
        !           134: /*
        !           135:  * This function is like "forwline", but goes backwards.
        !           136:  * The scheme is exactly the same.  Check for arguments that are
        !           137:  * less than zero and call your alternate. Figure out the new line and
        !           138:  * call "movedot" to perform the motion. No errors are possible.
        !           139:  * Bound to "C-P".
        !           140:  */
        !           141: backline(f, n)
        !           142: {
        !           143:        register LINE   *dlp;
        !           144: 
        !           145:        if (n < 0)
        !           146:                return (forwline(f, -n));
        !           147:        if ((lastflag&CFCPCN) == 0)             /* Reset goal if the    */
        !           148:                curgoal = curcol;               /* last isn't C-P, C-N  */
        !           149:        thisflag |= CFCPCN;
        !           150:        dlp = curwp->w_dotp;
        !           151:        while (n-- && lback(dlp)!=curbp->b_linep)
        !           152:                dlp = lback(dlp);
        !           153:        curwp->w_dotp  = dlp;
        !           154:        curwp->w_doto  = getgoal(dlp);
        !           155:        curwp->w_flag |= WFMOVE;
        !           156:        return (TRUE);
        !           157: }
        !           158: 
        !           159: /*
        !           160:  * This routine, given a pointer to a LINE, and the current cursor goal
        !           161:  * column, return the best choice for the offset. The offset is returned.
        !           162:  * Used by "C-N" and "C-P".
        !           163:  */
        !           164: getgoal(dlp)
        !           165: register LINE  *dlp;
        !           166: {
        !           167:        unsigned c;
        !           168:        register int    col;
        !           169:        register int    newcol;
        !           170:        register int    dbo;
        !           171: 
        !           172:        col = 0;
        !           173:        dbo = 0;
        !           174:        while (dbo != llength(dlp)) {
        !           175:                c = lgetc(dlp, dbo);
        !           176:                newcol = col;
        !           177:                switch (dblchr(c)) {
        !           178:                case 2:
        !           179:                        taber(newcol);
        !           180:                        break;
        !           181:                case 1:
        !           182:                        ++newcol;
        !           183:                }
        !           184:                ++newcol;
        !           185:                if (newcol > curgoal)
        !           186:                        break;
        !           187:                col = newcol;
        !           188:                ++dbo;
        !           189:        }
        !           190:        return (dbo);
        !           191: }
        !           192: 
        !           193: /*
        !           194:  * Scroll forward by a specified number of lines, or by a full page if
        !           195:  * no argument.
        !           196:  * The "2" in the arithmetic on the window size is the overlap; this value is
        !           197:  * the default overlap value in ITS EMACS. Because this zaps the top line in
        !           198:  * the display window, we have to do a hard update.
        !           199:  * Bound to "C-V".
        !           200:  */
        !           201: forwpage(f, n)
        !           202: register int   n;
        !           203: {
        !           204:        register LINE   *lp;
        !           205: 
        !           206:        if (f == FALSE) {
        !           207:                n = curwp->w_ntrows - 2;        /* Default scroll.      */
        !           208:                if (n <= 0)                     /* Forget the overlap   */
        !           209:                        n = 1;                  /* if tiny window.      */
        !           210:        } else if (n < 0)
        !           211:                return (backpage(f, -n));
        !           212: #if    CVMVAS
        !           213:        else                                    /* Convert from pages   */
        !           214:                n *= curwp->w_ntrows;           /* to lines.            */
        !           215: #endif
        !           216:        lp = curwp->w_linep;
        !           217:        while (n-- && lp!=curbp->b_linep)
        !           218:                lp = lforw(lp);
        !           219:        curwp->w_linep = lp;
        !           220:        curwp->w_dotp  = lp;
        !           221:        curwp->w_doto  = 0;
        !           222:        curwp->w_flag |= WFHARD;
        !           223:        return (TRUE);
        !           224: }
        !           225: 
        !           226: /*
        !           227:  * This command is like "forwpage", but it goes backwards.
        !           228:  * The "2", like above, is the overlap between the two windows. The
        !           229:  * value is from the ITS EMACS manual.  We do a hard update for exactly
        !           230:  * the same reason.
        !           231:  * Bound to "M-V".
        !           232:  */
        !           233: backpage(f, n)
        !           234: register int   n;
        !           235: {
        !           236:        register LINE   *lp;
        !           237: 
        !           238:        if (f == FALSE) {
        !           239:                n = curwp->w_ntrows - 2;        /* Default scroll.      */
        !           240:                if (n <= 0)                     /* Don't blow up if the */
        !           241:                        n = 1;                  /* window is tiny.      */
        !           242:        } else if (n < 0)
        !           243:                return (forwpage(f, -n));
        !           244: #if    CVMVAS
        !           245:        else                                    /* Convert from pages   */
        !           246:                n *= curwp->w_ntrows;           /* to lines.            */
        !           247: #endif
        !           248:        lp = curwp->w_linep;
        !           249:        while (n-- && lback(lp)!=curbp->b_linep)
        !           250:                lp = lback(lp);
        !           251:        curwp->w_linep = lp;
        !           252:        curwp->w_dotp  = lp;
        !           253:        curwp->w_doto  = 0;
        !           254:        curwp->w_flag |= WFHARD;
        !           255:        return (TRUE);
        !           256: }
        !           257: 
        !           258: /*
        !           259:  * Set the mark in the current window to the value of "." in the window.
        !           260:  * No errors are possible.
        !           261:  * Bound to "M-.".
        !           262:  */
        !           263: setmark(f, n)
        !           264: {
        !           265:        curwp->w_markp = curwp->w_dotp;
        !           266:        curwp->w_marko = curwp->w_doto;
        !           267:        mlwrite("[Mark set]");
        !           268:        return (TRUE);
        !           269: }
        !           270: 
        !           271: /*
        !           272:  * Swap the values of "." and "mark" in the current window.
        !           273:  * This is pretty easy, because all of the hard work gets done by the
        !           274:  * standard routine that moves the mark about. The only possible error is
        !           275:  * "no mark".
        !           276:  * Bound to "C-X C-X".
        !           277:  */
        !           278: swapmark(f, n)
        !           279: {
        !           280:        register LINE   *odotp;
        !           281:        register int    odoto;
        !           282: 
        !           283:        if (curwp->w_markp == NULL) {
        !           284:                mlwrite("No mark in this window");
        !           285:                return (FALSE);
        !           286:        }
        !           287:        odotp = curwp->w_dotp;
        !           288:        odoto = curwp->w_doto;
        !           289:        curwp->w_dotp  = curwp->w_markp;
        !           290:        curwp->w_doto  = curwp->w_marko;
        !           291:        curwp->w_markp = odotp;
        !           292:        curwp->w_marko = odoto;
        !           293:        curwp->w_flag |= WFMOVE;
        !           294:        return (TRUE);
        !           295: }
        !           296: 
        !           297: /*
        !           298:  * Go to a specific line in the buffer, mostly for
        !           299:  * looking up errors in C programs, which give the
        !           300:  * error a line number. If an argument is present, then
        !           301:  * it is the line number, else prompt for a line number
        !           302:  * to use.
        !           303:  */
        !           304: gotoline(f, n)
        !           305: register int   n;
        !           306: {
        !           307:        register LINE   *clp;
        !           308:        register int    s;
        !           309:        uchar           buf[32];
        !           310: 
        !           311:        if (f == FALSE) {
        !           312:                if ((s=mlreply("Goto line: ", buf, sizeof(buf))) != TRUE)
        !           313:                        return (s);
        !           314:                n = atoi(buf);
        !           315:        }
        !           316:        if (n <= 0) {
        !           317:                mlwrite("Bad line");
        !           318:                return (FALSE);
        !           319:        }
        !           320:        clp = lforw(curbp->b_linep);            /* "clp" is first line  */
        !           321:        while (n != 1) {
        !           322:                if (clp == curbp->b_linep) {
        !           323:                        mlwrite("Line too large");
        !           324:                        return (FALSE);
        !           325:                }
        !           326:                clp = lforw(clp);
        !           327:                --n;
        !           328:        }
        !           329:        curwp->w_dotp = clp;
        !           330:        curwp->w_doto = 0;
        !           331:        curwp->w_flag |= WFMOVE;
        !           332:        return (TRUE);
        !           333: }
        !           334: 
        !           335: /*
        !           336:  * Go to a specific line from the original file, mostly for
        !           337:  * looking up errors in C programs, which give the
        !           338:  * error a line number. If an argument is present, then
        !           339:  * it is the line number, else prompt for a line number
        !           340:  * to use.
        !           341:  */
        !           342: gotofline(f, n)
        !           343: register int   n;
        !           344: {
        !           345:        register LINE   *clp;
        !           346:        register int    s;
        !           347:        uchar           buf[32];
        !           348: 
        !           349:        if (f == FALSE) {
        !           350:                if ((s=mlreply("Goto line: ", buf, sizeof(buf))) != TRUE)
        !           351:                        return (s);
        !           352:                n = atoi(buf);
        !           353:        }
        !           354:        if (n <= 0) {
        !           355:                mlwrite("Bad line");
        !           356:                return (FALSE);
        !           357:        }
        !           358:        clp = lforw(curbp->b_linep);            /* "clp" is first line  */
        !           359:        while (n != l_number(clp)) {
        !           360:                if (clp == curbp->b_linep) {
        !           361:                        mlwrite("Line not in buffer");
        !           362:                        return (FALSE);
        !           363:                }
        !           364:                clp = lforw(clp);
        !           365:        }
        !           366:        curwp->w_dotp = clp;
        !           367:        curwp->w_doto = 0;
        !           368:        curwp->w_flag |= WFMOVE;
        !           369:        return (TRUE);
        !           370: }

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